1. Field of the Invention
This invention relates to an automatic speed-change control method and an automatic speed-change control apparatus of an actuator which automatically drives a mechanism such as a clutch etc. for changing the combination of meshing or engaging gears of a gear train for speed-change in a manual gear transmission of an automobile.
2. Description of the Related Art
A manual gear transmission of an automobile is basically provided with a gear train for speed-change, a change or switch mechanism for changing or switching a combination of the gear train, and an operating means for operating the change mechanism. For example, in the manual gear transmission in which the gear train for speed-change is mounted on a plurality of shafts in a meshed condition, the combination of gears is changed by shifting and selecting a synchromesh mechanism, which is one kind of clutch mechanism, by the operating means. Thus, rotating power from an engine is outputted after the speed-change.
A manual gear transmission has been developed involving an automatically operated type gear transmission in which a hydraulic actuator which can be controlled electrically or an electrical actuator for operating the clutch mechanism is provided in the operating means to be controlled by a command of ECU (Electronic Control Unit). In such automatically operated type manual gear transmission, the speed-change is performed in view of the durability of the synchromesh mechanism, and a reduction of the vehicle shock and noise.
That is, in the synchromesh-type gear transmission, there are for example four areas which include a shift-draw-out area to draw out a shift-select shaft from a shift fork, a select area to select the shift fork, a synchronize area where a synchronizer ring frictionally contacts with the gear, and a push-apart area where the sleeve meshes with the gear. As the time of the synchronize area is set shorter, the durability of the sleeve, the synchronizer ring and the cone etc. deteriorates, and as a shift shock speed at the push-apart area is set larger, vehicle shock and noise become remarkable.
In view of the above, in the manual gear transmission which has adopted the automatically operated method, an actuating amount or a driving amount of the hydraulic actuator or electrical actuator which operates the shift fork (a fluid speed or pressure in the hydraulic actuator, and a drive voltage or drive current in the electric actuator) is selected to be small so that the stroke speed of the shift fork is reduced, thereby setting the speed-change time to be relatively longer. In this way, the durability of the speed-change mechanism is increased, and the vehicle shock and the noise are reduced or attenuated. In other words, in the known manual gear transmission, the actuator is operated by seriously taking into account the durability increase of the speed-change mechanism and the reduction of the vehicle shock and noise.
However, in the synchromesh type gear transmission for example, the synchromesh mechanism which has been conventionally handled manually by a driver is automatically operated by an actuator for effecting the automatic speed-change, so the synchromesh transmission needs to be operated by an actuator in a manner equivalent to the manual operation. That is, the driver expects, when he or she kicks down or presses the accelerate pedal, that the actuator performs the quick speed-change to increase the vehicle speed in a short time. The above operation of the actuator which takes the mechanism durability and vehicle shock/noise reduction serious and ignores the speed-change timing is contrary to the driver's requirements for a speed-change time. Thus, the driver receives a strange feeling due to the delay in response of the speed-change mechanism.